Folding knife



FIG. 1 is a front elevational view of a folding knife, showing my new design;

FIG. 2 is a top plan view of the folding knife illustrated in FIG. 1;

FIG. 3 is a rear elevational view of the folding knife illustrated in FIG. 1;

FIG. 4 is a bottom plan view of the folding knife illustrated in FIG. 1;

FIG. 5 is a left side view of the folding knife illustrated in FIG. 1; and,

FIG. 6 is a right side view of the folding knife illustrated in FIG. 1. 

The ornamental design for a folding knife, as shown and described. 